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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (c) 2023 Daniel Golle <daniel@makrotopia.org>4 */5 6/* UBI NVMEM provider */7#include "ubi.h"8#include <linux/nvmem-provider.h>9 10/* List of all NVMEM devices */11static LIST_HEAD(nvmem_devices);12static DEFINE_MUTEX(devices_mutex);13 14struct ubi_nvmem {15 struct nvmem_device *nvmem;16 int ubi_num;17 int vol_id;18 int usable_leb_size;19 struct list_head list;20};21 22static int ubi_nvmem_reg_read(void *priv, unsigned int from,23 void *val, size_t bytes)24{25 size_t to_read, bytes_left = bytes;26 struct ubi_nvmem *unv = priv;27 struct ubi_volume_desc *desc;28 uint32_t offs;29 uint32_t lnum;30 int err = 0;31 32 desc = ubi_open_volume(unv->ubi_num, unv->vol_id, UBI_READONLY);33 if (IS_ERR(desc))34 return PTR_ERR(desc);35 36 offs = from % unv->usable_leb_size;37 lnum = from / unv->usable_leb_size;38 while (bytes_left) {39 to_read = unv->usable_leb_size - offs;40 41 if (to_read > bytes_left)42 to_read = bytes_left;43 44 err = ubi_read(desc, lnum, val, offs, to_read);45 if (err)46 break;47 48 lnum += 1;49 offs = 0;50 bytes_left -= to_read;51 val += to_read;52 }53 ubi_close_volume(desc);54 55 if (err)56 return err;57 58 return bytes_left == 0 ? 0 : -EIO;59}60 61static int ubi_nvmem_add(struct ubi_volume_info *vi)62{63 struct device_node *np = dev_of_node(vi->dev);64 struct nvmem_config config = {};65 struct ubi_nvmem *unv;66 int ret;67 68 if (!np)69 return 0;70 71 if (!of_get_child_by_name(np, "nvmem-layout"))72 return 0;73 74 if (WARN_ON_ONCE(vi->usable_leb_size <= 0) ||75 WARN_ON_ONCE(vi->size <= 0))76 return -EINVAL;77 78 unv = kzalloc(sizeof(struct ubi_nvmem), GFP_KERNEL);79 if (!unv)80 return -ENOMEM;81 82 config.id = NVMEM_DEVID_NONE;83 config.dev = vi->dev;84 config.name = dev_name(vi->dev);85 config.owner = THIS_MODULE;86 config.priv = unv;87 config.reg_read = ubi_nvmem_reg_read;88 config.size = vi->usable_leb_size * vi->size;89 config.word_size = 1;90 config.stride = 1;91 config.read_only = true;92 config.root_only = true;93 config.ignore_wp = true;94 config.of_node = np;95 96 unv->ubi_num = vi->ubi_num;97 unv->vol_id = vi->vol_id;98 unv->usable_leb_size = vi->usable_leb_size;99 unv->nvmem = nvmem_register(&config);100 if (IS_ERR(unv->nvmem)) {101 ret = dev_err_probe(vi->dev, PTR_ERR(unv->nvmem),102 "Failed to register NVMEM device\n");103 kfree(unv);104 return ret;105 }106 107 mutex_lock(&devices_mutex);108 list_add_tail(&unv->list, &nvmem_devices);109 mutex_unlock(&devices_mutex);110 111 return 0;112}113 114static void ubi_nvmem_remove(struct ubi_volume_info *vi)115{116 struct ubi_nvmem *unv_c, *unv = NULL;117 118 mutex_lock(&devices_mutex);119 list_for_each_entry(unv_c, &nvmem_devices, list)120 if (unv_c->ubi_num == vi->ubi_num && unv_c->vol_id == vi->vol_id) {121 unv = unv_c;122 break;123 }124 125 if (!unv) {126 mutex_unlock(&devices_mutex);127 return;128 }129 130 list_del(&unv->list);131 mutex_unlock(&devices_mutex);132 nvmem_unregister(unv->nvmem);133 kfree(unv);134}135 136/**137 * nvmem_notify - UBI notification handler.138 * @nb: registered notifier block139 * @l: notification type140 * @ns_ptr: pointer to the &struct ubi_notification object141 */142static int nvmem_notify(struct notifier_block *nb, unsigned long l,143 void *ns_ptr)144{145 struct ubi_notification *nt = ns_ptr;146 147 switch (l) {148 case UBI_VOLUME_RESIZED:149 ubi_nvmem_remove(&nt->vi);150 fallthrough;151 case UBI_VOLUME_ADDED:152 ubi_nvmem_add(&nt->vi);153 break;154 case UBI_VOLUME_SHUTDOWN:155 ubi_nvmem_remove(&nt->vi);156 break;157 default:158 break;159 }160 return NOTIFY_OK;161}162 163static struct notifier_block nvmem_notifier = {164 .notifier_call = nvmem_notify,165};166 167static int __init ubi_nvmem_init(void)168{169 return ubi_register_volume_notifier(&nvmem_notifier, 0);170}171 172static void __exit ubi_nvmem_exit(void)173{174 struct ubi_nvmem *unv, *tmp;175 176 mutex_lock(&devices_mutex);177 list_for_each_entry_safe(unv, tmp, &nvmem_devices, list) {178 nvmem_unregister(unv->nvmem);179 list_del(&unv->list);180 kfree(unv);181 }182 mutex_unlock(&devices_mutex);183 184 ubi_unregister_volume_notifier(&nvmem_notifier);185}186 187module_init(ubi_nvmem_init);188module_exit(ubi_nvmem_exit);189MODULE_DESCRIPTION("NVMEM layer over UBI volumes");190MODULE_AUTHOR("Daniel Golle");191MODULE_LICENSE("GPL");192